泸州区块页岩气地质工程一体化套变预防技术及应用

Geology-Engineering Integration Casing Deformation Prevention Technology and Its Application in Shale Gas,Luzhou Block

川南深层页岩气资源丰富,占整个川南页岩气资源量的80%以上,其中泸州区块又是当前川南深层页岩气上产的重点区域。尽管深层百亿方产能建设已全面启动,但受多期构造运动影响,川南深层页岩气开发仍面临构造特征复杂、断裂系统复杂、地应力复杂等诸多挑战,套变问题尤为突出。泸州区块页岩气井套变率高达53%,导致平台井EUR低,严重制约规模效益开发。针对以上问题,文章通过持续技术攻关与试验,在多级断裂和地应力精细刻画、应力场失稳评价等关键技术方面取得了显著性突破,形成了基于地质工程一体化工作模式的套变预防技术,研究结果表明,通过综合应用地质工程一体化套变预防技术,实现了从地质评价到钻井、压裂的全流程优化。科学优化了井眼轨迹,钻井过程中成功避开了主要的缝洞异常体和压力复杂带,压裂井套变率降至30%以下,成功实现了零丢段,平台井折算千米EUR提升超30%。泸州区块应用效果充分证明了地质工程一体化套变预防技术在预防套变和提升页岩气产量的重要作用,也为国内外深层页岩气规模效益开发提供了宝贵的技术参考。

The deep shale gas resources in south Sichuan are rich,accounting for more than 80%of the whole shale gas resources in south Sichuan,among which Luzhou block is the key area of deep shale gas production.Although the construction of 10 billion square meters of deep shale gas production capacity has been fully started,the development of deep shale gas still faces many challenges due to the influence of multi-stage tectonic movements,such as complex structural characteristics,complex fracture systems,and complex ground stresses,and the problem of casing deformation is particularly prominent.The casing deformation rate of shale gas wells in Luzhou block is as high as 53%,resulting in low EUR of platform wells,which seriously restricts the development of economies of scale.In view of the above problems,through continuous technical research and tests,significant breakthroughs have been made in key technologies such as multi-stage fault and ground stress fine characterization,stress field instability evaluation,etc.,and a set of casing deformation prevention technology based on working mode of geology-engineering integration has been formed.The results show that the optimization of the whole process from geological evaluation to drilling and fracturing can be realized through the comprehensive application of geologyengineering integration casing prevention technology.During the drilling process,the main fracture-cavity anomalies and pressure complex zones were avoided successfully,and the borehole trajectory was scientifically optimized.Frac well casing deformation rate decreased to less than 30%,zero lost stages were achieved,and platform well conversion kilometers EUR increased by more than 30%.The application in Luzhou block fully proves the important role of geology-engineering integration casing deformation prevention technology in preventing casing deformation and increasing shale gas production,and also provides a valuable technical reference for the scale economy development of deep shale gas at home and abroad.